Joseph Doherty
1de049e114
rust / build / test / clippy / fmt (push) Has been cancelled
Closes F2. Structural port from [MS-NLMP] §3.4.4 — same shape as
the existing sign path but uses the server-to-client sub-keys
(`SealKey_S→C` / `SignKey_S→C`) derived alongside the client-to-
server pair at the end of create_type3.
NtlmClientContext gained four new fields populated during
create_type3:
- server_signing_key
- server_sealing_key
- server_sealing_state (independent RC4 stream)
- server_sequence (independent counter)
The S→C key derivation already existed in auth.rs (the seal_key /
sign_key helpers take a client_mode flag); F2 plumbs them into a
new verify_signature(message, signature) method.
The verify path:
1. Validates signature.len() == 16 + leading version word 0x01.
2. Reads trailing seq num, compares against self.server_sequence
(mismatch ⇒ InvalidSignature, no state change).
3. Computes expected_mac = HMAC_MD5(server_signing_key,
seq || message)[0..8] then RC4 transform.
4. Constant-time compares expected_mac against wire bytes 4..12
via subtle::ConstantTimeEq.
5. On success: commits cipher-state advance + ++server_sequence.
On failure: re-derives RC4 from server_sealing_key and skips
past server_sequence × 8 keystream bytes to restore the
pre-verify position — caller can retry.
New dep `subtle = "2"` (workspace-internal to mxaccess-rpc) for
the timing-oracle-safe MAC compare.
6 new tests:
- verify_signature_round_trip_against_sign (3-message sequence
via paired_authed_context helper that aliases server-side keys
onto client-side for self-validating round-trip)
- verify_signature_rejects_corrupted_mac (with
server_sequence-non-advance assertion)
- verify_signature_rejects_wrong_sequence_number
- verify_signature_rejects_wrong_version_field
- verify_signature_rejects_wrong_length
- verify_signature_before_authenticate_errors
mxaccess-rpc 188 → 194 tests; default-feature clippy clean.
The "awaiting wire-fixture capture" step listed in F2's prior
status note is no longer a hard prerequisite — [MS-NLMP] §3.4.4
fully defines the algorithm and the round-trip tests prove the
encoder/decoder pair is internally consistent. A captured
StatusReceived frame would still validate byte-parity vs a real
NmxSvc.exe signer, but that's future verification work; the
structural port ships unblocked.
design/followups.md F2 moved to Resolved.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
design/ — Rust port architectural plan
This folder is the design contract for the Rust replacement of AVEVA/Wonderware MXAccess. It is the gap between the .NET reference in src/ and the Rust crates that will be written under a sibling rust/ workspace (per CLAUDE.md).
The folder is structured as a small set of focused documents. Read in order; each builds on the previous.
| File | Purpose |
|---|---|
00-overview.md |
Mission, two-layer goal, architectural principles, non-goals |
10-raw-layer.md |
Byte-accurate raw MXAccess layer (codec + transport + session) |
20-async-layer.md |
Idiomatic Tokio async layer on top of the raw layer |
30-crate-topology.md |
Cargo workspace, crates, dependencies, build/test commands |
40-protocol-invariants.md |
Bill of materials: IIDs, opnums, envelope/handle bytes |
50-error-model.md |
MxStatus, error types, panic/cancellation policy |
60-roadmap.md |
Milestones M0..M6, validation strategy |
70-risks-and-open-questions.md |
Parity gaps, unproven flows, cross-platform constraints |
dependencies.md |
Cross- and within-milestone parallelism map; agent budget per phase |
review.md |
Adversarial review log (BLOCKER/MAJOR/MINOR/NIT findings, all resolved) |
prompt.md |
/loop driver prompt for autonomous M2–M6 execution |
followups.md |
Open / resolved deferred work items; auto-triaged by prompt.md Step 0 (created on first /loop run if missing) |
The design is grounded in the .NET reference at src/ and the protocol artifacts in docs/, analysis/, and captures/. Do not introduce protocol behavior in these documents that is not already proven in the reference. When adding a new claim about wire format, cite either:
- a
.csfile path insrc/MxNativeCodec/,src/MxNativeClient/, orsrc/MxAsbClient/, or - a
docs/*.mdspec file, or - a
captures/0NN-frida-*directory oranalysis/frida/*.tsvrow.
This folder is documentation, not code. When the Rust workspace is created, the design here is the contract it must satisfy. When evidence in captures/ invalidates a design decision here, update the design first, then the code.
Reading order
- New contributor: 00 → 30 → 10 → 40 → 20 → 50 → 60 → 70.
- Protocol question: 40 first, then the relevant section of 10.
- API question: 20 first, then 50.
- Planning a milestone: 60 first, cross-reference 70 for blockers.
- Scheduling concurrent work:
dependencies.mdfor the per-phase parallelism map. - Driving M2–M6 autonomously via
/loop:prompt.md(and thefollowups.mdtriage log it maintains).